The subject invention relates to a conveyance structural improvement of continuous type heating oven, particularly to one that will effectively avoid the occurrence of dropping plate, jamming plate, clamped plate, etc.
Surface mount technology has improved on many weaknesses in the conventional type of penetrated-hole circuit board, application of such technology has reduced the cubic measurements of a product, increased its density, saved manpower and achieved the precision that could not be performed by manpower, therefore, it is highly commended by the manufacturing industry, many peripheral equipment have been introduced since, such as surface adhering components, positioning machine, spot welder, soldering furnace, etc.
Conventionally, a continuous type heating oven is designed to achieve welding purposes by heating the SMD component pins, solder and working piece with a heater. A conventional type of continuous heating oven involves a proper conveyance unit, which serves to convey a printed circuit board (PCB) through the heater in the machine unit to enable welding operation, the conveyance structure of a conventional type of continuous heating oven is shown in FIG. 1, said conveyance unit comprises a mesh conveyor belt 1A and a chain conveyor unit 2A, said mesh conveyor belt 1A and the chain conveyor unit 2A are respectively driven by a driving mechanism to perform continuous conveyance, a foundation plate may be carried on the two sides between the two chains of the chain conveyor unit 2A, the mesh conveyor belt 1A may serve to take up the foundation plate that drops by accident, or to carry a foundation plate with a smaller area.
However, in the conveyor unit of said conventional type of continuous heating oven, the chain conveyor unit 2A is installed on the surrounding of the mesh conveyor belt 1A, therefore, the length of the mesh conveyor belt 1A must be shorter than the chain conveyor unit 2A, therefore, there shall be a clearance below the two ends of the chain conveyor unit 2A without the equipment of the mesh conveyor belt 1A, and, to avoid close contact between the mesh conveyor belt 1A and the chain conveyor unit 2A during the operation, there must be a specified distance between the two parts, but such requirement shall lengthen the clearance L below the two ends of the chain conveyor unit 2A where there is no mesh conveyor belt 1A, such occurrence of said clearance L will easily cause the conveying foundation plate to drop from the output, or jam or clamped in said clearance, and such occurrence of dropping plate, jamming plate or clamped plate has been regarded by the manufacturers as a major defect. Moreover, the axis of the chain wheel of the chain conveyor unit 2A is in horizontal arrangement, while the chains' conveyance is in vertical takeover arrangement, and at the sides of the chains are the extensions of carrying protrusions, to carry the foundation plate or other objects to be conveyed on two sides, in such an operation, the foundation plate will easily jam between the carrying protrusions, and at the input end where the takeover process is performed the plate will easily be clamped, moreover, the chains carry the load of the foundation plate merely with the carrying protrusions, therefore, the foundation plate will be supported by the carrying protrusions only horizontally, as a result, the foundation plate will not be steadily conveyed on the chains.
Therefore, in the sense of actual applications, the conveyor unit of said conventional type of continuous heating oven does involve inconveniences and weaknesses that need further improvement.
In view of effective improvement of the above, the subject inventor has devoted intensive study, with technical applications, and has finally presented the reasonably designed subject invention with effective improvement of the above weaknesses.